There are many problems in formulating topical compositions. In order to be commercially acceptable, the composition must be stable. No matter how efficacious a product is, the product will not be commercially acceptable if it separates or otherwise deteriorates under normal shipping and storage conditions prior to sale. In addition, when compositions applied to the skin are meant to form a film, it is important that the film formed be relatively homogeneous on the skin. One criterion for assessing the adequacy of a film formed on skin is spreadability, which means that when a composition is applied to skin it should spread onto the skin to form a relatively even film. This is particularly important when it comes to color cosmetics and sunscreens. Obviously a sun bather does not want to apply a sunscreen film that leaves gaps in coverage, nor does a consumer want to apply a lipstick that does not evenly color the lips. It is believed that spreadability and relatively homogeneous film formation on skin is improved when the composition is formulated with ingredients that improve dispersibility of various components such as particulates, oils, and polymers, in the composition.
Cyanodiphenylacrylates are generally known for enhancing SPF when incorporated into sunscreens. U.S. Patent Publication 2009/0039323A1 teaches that certain α-cyanodiphenylacrylates act by accepting the triplet excited state energy generated by organic sunscreens such as Avobenzone when it is exposed to certain environmental conditions. The end result is that the excess energy formed by the unstable Avobenzone is then dissipated and does not result in an unstable ingredient that compromises the stability of the formula. However, cosmetic formulators must combine more than cyanodiphenylacrylates and organic sunscreens to make a commercially acceptable cosmetic formula, particularly when it may contain other ingredients. One formulation concern is aesthetics. No matter how efficacious a product is, consumers will not buy it if it is aesthetically unpleasant when applied to skin. In order to improve aesthetics, cosmetic formulators use light, dry oils such as silicones. Silicones provide aesthetically pleasing cosmetic formulas but contribute to certain disadvantages when it comes to film formation on skin. In particular, cosmetics containing silicone may provide uneven film formation on skin surfaces. This is an obvious disadvantage when formulating products such as sunscreens, where an even film on skin is desired.
It has been found that in addition to its SPF enhancing capability, certain α-cyanodiphenylacrylates, despite their lipophilic character, are excellent dispersants for cosmetic ingredients, including those that are polar or that may contain both lipophilic and hydrophilic moieties. The combination of α-cyanodiphenylacrylates with oxyalkylenated organosiloxanes is particularly effective in forming topical cosmetic products that provide a spreadable, smooth and even film when applied to skin. Most unexpectedly, the α-cyanodiphenylacrylates are compatible with both silicones and organosiloxane emulsifiers, enabling formation of composition that provide a smooth and even film on skin where the ingredients present are dispersed in the composition. When dispersion of cosmetic ingredients is optimized the composition exhibits maximum effectiveness in forming a film on skin, improving SPF protection, and providing commercially acceptable aesthetics.